A legislative aide for state Senate President Therese Murray told a federal jury Friday that she helped guide a politically connected job applicant toward a position with the Probation Department on Murray’s behalf, an applicant other witnesses have described as woefully underqualified.

It was the first testimony connecting a high-ranking legislator to the alleged corrupt hiring practices at the Probation Department.

Francine Gannon, Murray’s constituent services coordinator for seven years, testified that Murray’s friend and former campaign manager Kevin O’Reilly first lobbied her in February 2008 for a job for Patrick Lawton, whose father and grandfather were judges.

Murray herself, Gannon said, also asked her at one point, “How are we doing on him?” referring to Lawton’s hiring.

By May 2, 2008, Gannon was notified by a liaison for the Probation Department that Lawton would be offered a job the following Monday, though he had not yet been told. Murray decided she would contact Lawton’s mother, a friend, to tell her the news, Gannon testified.

“He should be all set,” Gannon said in a May 29, 2008, memo to Murray.

Two years later, Lawton, who a judge on Thursday testified was inadequate in the job and should never have been hired, resigned after he was arrested on a charge of possessing heroin.

Gannon was the sixth witness to testify in the federal trial alleging a corrupt hiring process in the Probation Department, and prosecutors sought to use her testimony to show the influence of legislators in the department’s hiring.

An aide for Murray said the Senate president would not comment on an ongoing trial. Murray has said before that she did nothing wrong in sponsoring Probation Department candidates. Defense lawyers have said they may call her to testify that patronage was a common practice on Beacon Hill.

The former probation commissioner, John J. O’Brien, and top aides Elizabeth Tavares and William Burke III are charged with racketeering and mail fraud for allegedly running their department like a criminal enterprise, by directing jobs to the friends and family members of state legislators. In exchange, prosecutors alleged, the legislators significantly boosted the department’s budget, helping probation officials to build their political power, using jobs as “political currency.”

Defense lawyers have argued that their clients did nothing illegal, even if they were engaged in political patronage. In a legal victory for the defense Friday, US District Court Judge William G. Young said he will allow the lawyers to present documents showing Gannon helped people get other jobs within the trial court system, specifically as court officers, and that top officials including Robert Mulligan, then chief justice for administration of the trial courts and O’Brien’s supervisor, knew that patronage hiring was a common practice.

A judge on the Plymouth Probate and Family Court who served on a Probation Department hiring panel told jurors Thursday that she opposed the hiring of Lawton, whose appointment was one of the 40 examples of corrupt hiring that prosecutors have listed in a sweeping indictment.

Judge Catherine Sabaitis said she watched in disappointment as probation officials manipulated the hiring process on Lawton’s behalf. Sabaitis said she was told that the commissioner’s office wanted Lawton appointed.

During cross-examination Friday morning, Sabaitis agreed that she has sought the support of politicians when seeking jobs, including her judgeship. And she acknowledged that she has previously hired people who did not receive the top ranking in an interview.

“[Did] the federal government ever come down and indict you for that?” Stellio Sinnis, a lawyer for O’Brien, asked pointedly.

Gannon, a Boston native, said she had worked for former US representatives John Joseph Moakley and House speaker Thomas P. O’Neill Jr., as well as former state Senate president Robert Travaglini, before working for Murray as constituent services coordinator.

She said she would record her work, including her attempts to direct people to jobs, on a “case sheet,” and she outlined for Assistant US Attorney Karin Bell her efforts to secure a job for Lawton.

Initially, he had requested a job as a hearing officer for the Registry of Motor Vehicles, or, failing that, a position in the Department of Public Safety.

Later, Lawton’s father, Mark, a retired judge and state representative, wrote Gannon asking her to consider his son for a job as a probation officer at the Plymouth courthouse.

“I know that Jack O’Brien takes very seriously calls from your office where there is a strong interest on the part of the Senate president,” Mark Lawton wrote.

By mid-May, Lawton had been hired. He brought a bouquet of flowers to Gannon.